Brassicaceae plant colorants, which are anthocyanin colorants, are widely used, mainly in the coloring of beverages and other edible products. However, a Brassicaceae plant colorant has a distinctive vegetable or pickle odor that comes from its raw material, Brassicaceae plants, so when it is used in foods, cosmetics, and other such products, this odor can sometimes undesirably taint the flavor, taste and aroma of these products.
Consequently, there has long been a need for a Brassicaceae plant colorant formulation that can be added to foods and so forth and an aroma component therein has been reduced to the point that the distinctive odor of Brassicaceae plants is undetectable, and various purification methods have been examined up to now. Methods that have been proposed include a method in which an extract of red cabbage is treated with an adsorption resin or an ion exchange resin (Japanese Patent Examined Publication S62-18581), a method in which a water-soluble edible colorant is extracted with an organic solvent or supercritical carbon dioxide (Japanese Patent Examined Publication H4-48420), and a method in which a water or alcohol solution of an anthocyanin colorant is treated with a cation exchange resin, a silica gel (deodorization), an ultrafiltration membrane that removes molecules with a molecular weight of approximately 20,000 or higher, or the like (Japanese Patent Examined Publication H4-41185).
However, although colorant formulations containing a Brassicaceae plant colorant prepared by these treatments do indeed have less odor than a colorant formulation containing an untreated colorant, the fact remains that they still cannot be considered satisfactory colorant formulations.
Also, conventional Brassicaceae plant colorant formulations have been indicated as having a so-called “return smell,” that is, the odor gradually becomes stronger over time as a result of heating or extended storage, and this problem of “return smell” has yet to be resolved with the various purification treatments discussed above.